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| Computer networks. Classification of computer networks |
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Content Introduction Chapter 1 Concept and classification of computer networks 1.1 Purpose of a computer network 1.2 Classification of computer networks Chapter 2. Main types of computer networks 2.1 Local area network (LAN) 2.2 Global Area Network (WAN) Conclusion List of used literature Introduction Russia’s entry into the global information space entails the widest use of the latest information technologies, and first of all, computer networks. At the same time, the user’s capabilities sharply increase and qualitatively change both in providing services to their clients and in solving their own organizational and economic problems. It is appropriate to note that modern computer networks are a system whose capabilities and characteristics generally significantly exceed the corresponding indicators of the simple sum of the constituent elements of a network of personal computers in the absence of interaction between them. The advantages of computer networks have led to their widespread use in information systems of the credit and financial sector, government and local governments, enterprises and organizations. Computer networks and network information processing technologies have become the basis for building modern information systems. The computer should now be considered not as a separate processing device, but as a “window” into computer networks, a means of communication with network resources and other network users. In recent years, the global Internet has become a global phenomenon. The network, which until recently was used by a limited number of scientists, government officials and employees of educational institutions in their professional activities, has become available to large and small corporations and even to individual users. The purpose of this coursework is to familiarize yourself with the basics of the construction and operation of computer networks, to study the organization of computer networks. To achieve this goal, it is necessary to solve a number of problems: Introduction to computer networks, highlighting their features and differences; Characteristics of the main methods of constructing networks (network topology); Studying scientific and methodological literature on this issue Chapter 1 Concept and classification of computer networks 1.1 Purpose of a computer network The main purpose of computer networks is to share resources and implement interactive communications both within one company and outside it. Resources are data, applications, and peripheral devices such as an external disk drive, printer, mouse, modem, or joystick. Computers included in the network perform the following functions: Organization of Internet access Information transfer management Providing computing resources and services to network users. Currently, local computing (LAN) has become very widespread. This is due to several reasons: Connecting computers into a network allows you to significantly save money by reducing the cost of maintaining computers (it is enough to have a certain disk space on the file server (the main computer of the network) with software products installed on it, used by several workstations); Local networks allow you to use Mailbox to transfer messages to other computers, which allows you to transfer documents from one computer to another in the shortest possible time; Local networks, if there is a special software(software) are used to organize the sharing of files (for example, accountants on several machines can process entries of the same ledger). Among other things, in some areas of activity it is simply impossible to do without a LAN. These areas include: banking, warehouse operations of large companies, electronic archives of libraries, etc. In these areas, each individual workstation, in principle, cannot store all the information (mainly due to its too large volume). A global computer network is a network connecting computers located geographically at great distances from each other. It differs from a local network in having longer communications (satellite, cable, etc.). The global network connects local networks. The Internet, which once served exclusively research and academic groups whose interests ranged from access to supercomputers, is becoming increasingly popular in the business world. 1.2 Classification of computer networks Based on the method of organization, networks are divided into real and artificial. Artificial networks (pseudo-networks) allow you to connect computers together via serial or parallel ports and do not require additional devices. Sometimes communication in such a network is called communication via a null modem (no modem is used). Self-connection is called null-modem. Artificial networks are used when it is necessary to transfer information from one computer to another. MS-DOS and Windows are equipped with special programs for implementing a null modem connection. Real networks allow computers to be connected using special switching devices and a physical data transmission medium. /> The territorial distribution of networks can be local, global, regional and city. Local Area Network (LAN) - Local Area Networks (LAN) is a group (communication system) of a relatively small number of computers united by a shared data transmission medium, located in a limited small area within one or more nearby buildings (usually within a radius of no more than 1 -2 km) in order to share the resources of all computers A global computer network (WAN or WAN - World Area NetWork) is a network connecting computers that are geographically distant from each other. Differs from a local network in more extensive communications (satellite, cable, etc.). The global network connects local networks. Metropolitan Area Network (MAN - Metropolitan Area NetWork) is a network that serves the information needs of a large city. Regional - located on the territory of a city or region. Also, recently experts have identified this type of network as a banking one, which is a special case of the corporate network of a large company. It is obvious that the specifics of banking activities impose strict requirements on information protection systems in the bank’s computer networks. An equally important role when building a corporate network is played by the need to ensure trouble-free and uninterrupted operation, since even a short-term failure in its operation can lead to huge losses. There are departmental and state networks based on their affiliation. Departmental ones belong to one organization and are located on its territory. Government networks are networks used in government agencies. Based on the speed of information transfer, computer networks are divided into low-, medium- and high-speed. low-speed (up to 10Mbit/s), medium-speed (up to 100Mbit/s), high-speed (over 100 Mbit/s); Depending on the purpose and technical solutions networks can have different configurations (or, as they also say, architecture, or topology). In a ring topology, information is transmitted over a closed channel. Each subscriber is directly connected to its two closest neighbors, although in principle it is capable of contacting any subscriber in the network. In a star-shaped (radial) system, in the center there is a central control computer that sequentially communicates with subscribers and connects them with each other. In a bus configuration, computers are connected to a common channel (bus), through which they can exchange messages. In a tree view, there is a “main” computer, to which the computers of the next level are subordinate, etc. In addition, configurations without a distinct nature of connections are possible; The limit is a fully meshed configuration, where every computer on the network is directly connected to every other computer. From the point of view of organizing the interaction of computers, networks are divided into peer-to-peer (Peer-to-Peer Network) and dedicated server (Dedicated Server Network). All computers in a peer-to-peer network have equal rights. Any network user can access data stored on any computer. Peer-to-peer networks can be organized using operating systems such as LANtastic, Windows "3.11, Novell Netware Lite. Specified programs Works with both DOS and Windows. Peer-to-peer networks can also be organized on the basis of all modern 32-bit operating systems - Windows 9x\ME\2k, Windows NTworkstation version, OS/2) and some others. Advantages of peer-to-peer networks: 1) the easiest to install and operate. 2) the DOS and Windows operating systems have all the necessary functions that allow you to build a peer-to-peer network. The disadvantage of peer-to-peer networks is that it is difficult to resolve information security issues. Therefore, this method of organizing a network is used for networks with a small number of computers and where the issue of data protection is not fundamental. In a hierarchical network, when the network is installed, one or more computers are pre-allocated to manage data exchange over the network and resource distribution. Such a computer is called a server. Any computer that has access to the server's services is called a network client or workstation. A server in hierarchical networks is a permanent storage of shared resources. The server itself can only be a client of a server at a higher hierarchy level. Therefore, hierarchical networks are sometimes called dedicated server networks. Servers are usually high-performance computers, possibly with several parallel processors, high-capacity hard drives, and a high-speed network card (100 Mbit/s or more). The hierarchical network model is the most preferable, as it allows you to create the most stable network structure and more rationally distribute resources. Another advantage of a hierarchical network is a higher level of data protection. The disadvantages of a hierarchical network, compared to peer-to-peer networks, include: 1) the need for an additional OS for the server. 2) higher complexity of network installation and upgrading. 3) The need to allocate a separate computer as a server. Chapter 2 Main types of computer networks 2.1 Local area network (LAN) Local networks (LAN computers) connect a relatively small number of computers (usually from 10 to 100, although sometimes much larger ones are found) within one room (a computer classroom), building or institution (for example, a university). The traditional name is a local area network (LAN). ) - rather a tribute to the times when networks were mainly used to solve computing problems; today, in 99% of cases, we are talking exclusively about the exchange of information in the form of texts, graphic and video images, and numerical arrays. The usefulness of the LS is explained by the fact that from 60% to 90% of the information an institution needs circulates within it, without needing to go outside. The development of drugs was greatly influenced by the creation of automated enterprise management systems (ACS). ACS include several automated workstations (AWS), measuring systems, and control points. Another important field of activity in which drugs have proven their effectiveness is the creation of classroom-based computer technology (KUTT). Thanks to the relatively short lengths of communication lines (usually no more than 300 meters), information can be transmitted via LAN to digital form with high transmission speed. Over long distances, this transmission method is unacceptable due to the inevitable attenuation of high-frequency signals; in these cases, it is necessary to resort to additional technical (digital-to-analog conversions) and software (error correction protocols, etc.) solutions. A characteristic feature of the LAN is the presence of a high-speed communication channel connecting all subscribers for transmitting information in digital form. There are wired and wireless channels. Each of them is characterized by certain values of parameters that are essential from the point of view of drug organization: Data transfer rates; Maximum line length; Noise immunity; Mechanical strength; Convenience and ease of installation; Cost. Currently, four types of network cables are commonly used: Coaxial cable; Unprotected VitayaPara; Protected twisted pair; Fiber optic cable. The first three types of cables transmit an electrical signal through copper conductors. Fiber optic cables transmit light along glass fibers. Most networks allow several cable connection options. Coaxial cables consist of two conductors surrounded by insulating layers. The first layer of insulation surrounds the central copper wire. This layer is braided from the outside with an external shielding conductor. The most common coaxial cables are thick and thin "Ethernet" cables. This design provides good noise immunity and low signal attenuation over distances. There are thick (about 10 mm in diameter) and thin (about 4 mm) coaxial cables. Having advantages in noise immunity, strength, and league length, a thick coaxial cable is more expensive and more difficult to install (it is more difficult to pull through cable channels) than a thin one. Until recently, thin coaxial cable represented a reasonable compromise between the basic parameters of LAN communication lines and in Russian conditions is most often used for organizing large LANs of enterprises and institutions. However, thicker, more expensive cables provide better data transmission over longer distances and are less susceptible to electromagnetic interference. Twisted pairs are two wires twisted together at six turns per inch to provide EMI protection and impedance matching. Another name usually used for such wire is "IBM Type-3". In the USA, such cables are installed during the construction of buildings to provide telephone communication. However, using telephone wire, especially when it is already placed in a building, can create big problems. First, unprotected twisted pair cables are susceptible to electromagnetic interference, such as electrical noise generated by fluorescent lamps and moving elevators. Interference can also be caused by closed-loop signals on telephone lines running along a LAN cable. In addition, poor quality twisted pair cables may have a variable number of turns per inch, which distorts the calculated electrical resistance. It is also important to note that telephone wires are not always laid in a straight line. A cable connecting two adjacent rooms can actually go around half the building. Underestimating the cable length in this case may result in it actually exceeding the maximum permissible length. Protected twisted pairs are similar to unprotected twisted pairs, except that they use thicker wires and are protected from external influences by the neck of the insulator. The most common type of such cable used in local networks, “IBM type-1” is a secure cable with two twisted pairs of continuous wire. In new buildings the best option may be a “type-2” cable, since it includes, in addition to the data transmission line, four unprotected pairs of continuous wire for transmitting telephone conversations. Thus, “type-2” allows you to use one cable to transmit both telephone conversations and data over a local network. Protection and careful adherence to the number of twists per inch make rugged twisted pair cable a reliable alternative cabling connection.” However, this reliability comes at an increased cost. Fiber optic cables transmit data in the form of pulses of light" to glass "wires". Most LAN systems today support fiber optic cabling. Fiber optic cable has significant advantages over any copper cable option. Fiber optic cables provide the highest transmission speeds; they are more reliable because they are not subject to loss of information packets due to electromagnetic interference. Optical cable is very thin and flexible, making it easier to transport than heavier copper cable. Most importantly, however, only optical cable has the bandwidth needed for faster networks in the future. The price of fiber optic cable is still significantly higher than copper cable. Compared to copper cable, the installation of an optical cable is more labor-intensive, since its ends must be carefully polished and aligned to ensure a reliable connection. However, now there is a transition to fiber-optic lines, which are absolutely immune to interference and are unrivaled in terms of throughput. The cost of such lines is steadily decreasing, technological difficulties The junctions of optical fibers are successfully overcome. Wireless communications over microwave radio waves can be used to organize networks within large premises such as hangars or pavilions, where the use of conventional communication lines is difficult or impractical. In addition, wireless lines can connect remote segments of local networks at distances of 3 - 5 km (with a wave channel antenna) and 25 km (with a directional parabolic antenna) subject to direct visibility. Organizing a wireless network is significantly more expensive than a conventional one. To connect computers using LAN communication lines, network adapters (or, as they are sometimes called, network cards) are required. The most famous are: adapters of the following three types: Of these, the latter have become overwhelmingly widespread in Russia. The network adapter is inserted directly into a free slot on the motherboard of a personal computer and a LAN communication line is connected to it on the rear panel of the system unit. The adapter, depending on its type, implements one or another access strategy from one computer to another. To ensure coordinated operation in data networks, various communication protocols are used - sets of rules that the transmitting and receiving parties must adhere to for consistent data exchange. Protocols are sets of rules and procedures that govern how some communication occurs. Protocols are the rules and technical procedures that allow multiple computers, when networked, to communicate with each other. There are many protocols. And although they all participate in the implementation of communication, each protocol has different goals, performs different tasks, and has its own advantages and limitations. Protocols operate at different levels of the OSI/ISO open systems interconnection model. The functions of a protocol are determined by the level at which it operates. Several protocols can work together. This is the so-called stack, or set, of protocols. Just as networking functions are distributed across all layers of the OSI model, protocols operate together at different layers of the protocol stack. Layers in the protocol stack correspond to layers of the OSI model. Taken together, the protocols provide a complete description of the functions and capabilities of the stack. Data transmission over a network, from a technical point of view, must consist of sequential steps, each of which has its own procedures or protocol. Thus, a strict sequence in performing certain actions is maintained. In addition, all these steps must be performed in the same sequence on each network computer. On the sending computer, actions are performed from top to bottom, and on the receiving computer, from bottom to top. The sending computer, in accordance with the protocol, performs the following actions: breaks the data into small blocks called packets that the protocol can work with, adds address information to the packets so that the recipient computer can determine that this data is intended for it, prepares the data for transmission through the network adapter card and then via the network cable. The recipient computer, in accordance with the protocol, performs the same actions, but only in reverse order: receives data packets from the network cable; transmits data to the computer through the network adapter card; removes from the packet all service information added by the sending computer, copies the data from the packet to a buffer - to combine it into the original block, transfers this block of data to the application in the format that it uses. Both the sending computer and the receiving computer need to perform each action in the same way so that the data received over the network matches the data sent. If, for example, the two protocols have different ways of breaking up data into packets and adding information (packet sequence, timing, and error checking), then a computer running one of those protocols will not be able to successfully communicate with a computer running the other protocol. Until the mid-80s, most local networks were isolated. They served individual companies and were rarely combined into large systems. However, when local networks reached a high level of development and the volume of information transmitted by them increased, they became components of large networks. Data transmitted from one local network to another along one of the possible routes is called routed. Protocols that support data transfer between networks along multiple routes are called routed protocols. Among the many protocols, the most common are the following: · IPX/SPX and NWLmk; · OSI protocol suite. 2.2 Wide Area Network (WAN) WAN (World Area Network) is a global network covering large geographic regions, including both local networks and other telecommunication networks and devices. An example of a WAN is a packet-switched network (Frame relay), through which various computer networks can “talk” to each other. Today, when the geographical boundaries of networks are expanding to connect users from different cities and states, LANs are turning into a global computer network [WAN], and the number of computers in the network can already vary from tens to several thousand. Internet is a global computer network covering the whole world. Today the Internet has about 15 million subscribers in more than 150 countries around the world. Every month the size of the network increases by 7-10%. The Internet forms, as it were, a core that provides communication between various information networks, belonging to various institutions around the world, one with another. If previously the network was used exclusively as a medium for transferring files and email messages, today more complex problems of distributed access to resources are being solved. About three years ago, shells were created that support network search functions and access to distributed information resources and electronic archives. The Internet, which once served exclusively research and academic groups whose interests ranged from access to supercomputers, is becoming increasingly popular in the business world. Companies are seduced by speed, cheap global communications, ease of collaboration, accessible programs, and a unique Internet database. They view the global network as a complement to their own local networks. At a low cost (often just a flat monthly fee for the lines or telephone used), users can access commercial and non-commercial information services in the United States, Canada, Australia, and many European countries. In the archives of free access on the Internet you can find information on almost all areas of human activity, from new scientific discoveries to the weather forecast for tomorrow. In addition, the Internet provides unique opportunities for low-cost, reliable and confidential global communications around the world. This turns out to be very convenient for companies with their branches around the world, transnational corporations and management structures. Typically, using the Internet infrastructure for international communication is much cheaper than direct computer communications through satellite channel or via telephone. E-mail is the most common Internet service. Currently, approximately 20 million people have an email address. Sending a letter by e-mail is much cheaper than sending a regular letter. In addition, the message sent via e-mail will reach the addressee in a few hours, while a regular letter can take several days, or even weeks, to reach the addressee. Currently, the Internet uses almost all known communication lines from low-speed telephone lines to high-speed digital satellite channels. In fact, the Internet consists of many local and global networks, belonging to different companies and enterprises, interconnected by various communication lines. The Internet can be imagined as a mosaic made up of small networks of different sizes that actively interact with each other, sending files, messages, etc. Like any other network on the Internet, there are 7 levels of interaction between computers: physical, logical, network, transport, session level, presentation and application level. Accordingly, each level of interaction corresponds to a set of protocols (i.e. rules of interaction). Physical layer protocols determine the type and characteristics of communication lines between computers. The Internet uses almost all currently known communication methods, from a simple wire (twisted pair) to fiber-optic communication lines (FOCL). For each type of communication line, a corresponding logical level protocol has been developed to control the transmission of information over the channel. Logical layer protocols for telephone lines include SLIP (Serial Line Interface Protocol) and PPP (Point to Point Protocol). For communication over a cable local network, these are packet drivers for LAN cards. Network layer protocols are responsible for transmitting data between devices on different networks, that is, they are responsible for routing packets in the network. Network layer protocols include IP (Internet Protocol) and ARP (Address Resolution Protocol). Transport layer protocols control the transfer of data from one program to another. Transport layer protocols include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). Session-level protocols are responsible for establishing, maintaining and destroying the corresponding channels. On the Internet, the already mentioned TCP and UDP protocols, as well as the UUCP (Unix to Unix Copy Protocol). Representative layer protocols are responsible for serving application programs. Representative-level programs are programs that run, for example, on a Unix server, to provide various services to subscribers. These programs include: telnet server, FTP server, Gopher server, NFS server, NNTP (Net News Transfer Protocol), SMTP (Simple Mail Transfer Protocol), POP2 and POP3 (Post Office Protocol), etc. Application layer protocols include network services and programs for providing them. The Internet is a constantly developing network, which still has everything ahead, let’s hope that our country will not lag behind the progress. />/>/>/>/>/>/>/>/>/>/>/>Conclusion A computer network is an association of several computers for the joint solution of information, computing, educational and other problems. The main purpose of computer networks is to share resources and implement interactive communication both within one company and and beyond. A local computer network is a collection of computers connected by communication lines, providing network users with the potential opportunity to share the resources of all computers. On the other hand, simply put, a computer network is a collection of computers and various devices, providing information exchange between computers on a network without the use of any intermediate storage media. A global computer network (WAN or WAN - World Area NetWork) is a network that connects computers that are geographically located at large distances from each other. It differs from a local network in more extensive communications (satellite, cable, etc.). The global network connects local networks. Internet is a global computer network covering the whole world. In fact, the Internet consists of many local and global networks belonging to various companies and enterprises, interconnected by various communication lines. List of used literature 1. “Internet at your home”, S. V. Simonovich, V. I. Murakhovsky, LLC “AST-Press Book”, Moscow 2002. 2. Gerasimenko V.G., Nesterovsky I.P., Pentyukhov V.V. and others. Computer networks and means of their protection: Textbook / Gerasimenko V.G., Nesterovsky I.P., Pentyukhov V.V. and etc. – Voronezh: VSTU, 1998. – 124 p. 3. ComputerWeek Moscow, a weekly magazine for entrepreneurs and specialists in the field of information technology. 4. Magazine for personal computer users PC World. 5. Kamalyan A.K., Kulev S.A., Nazarenko K.N. and others. Computer networks and information security tools: Textbook / Kamalyan A.K., Kulev S.A., Nazarenko K.N. and others - Voronezh: VSAU, 2003.-119p. 6. Kurnosov A.P. Workshop on computer science/Ed. Kurnosova A.P. Voronezh: VSAU, 2001.- 173 p. 7. Malyshev R.A. Local computer networks: Textbook / RGATA. – Rybinsk, 2005. – 83 p. 8. Olifer V.G., Olifer N.A. Network operating systems/ V.G. Olifer, N.A. Olifer. – St. Petersburg: Peter, 2002. – 544 p.: ill. 9. Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols/V.G. Olifer, N.A. Olifer. - St. Petersburg: Peter, 2002.- 672 p.: ill. 10. Simonovich S.V. Informatics. Basic course/Simonovich S.V. and others - St. Petersburg: Peter Publishing House, 2000. - 640 pp.: ill. (Graduate work) n1.doc1 TPI Prilepo D.V. Content Page
IntroductionPurpose practice is to consolidate theoretical knowledge and develop sustainable practical skills in collecting, storing, processing, analyzing and presenting information on personal computers. To achieve the goal you need to do the following tasks:
1. GENERAL PART The branch is a structural subdivision of the state educational institution professional higher education"Kostroma State University named after. ON THE. Nekrasova". The branch is endowed, by power of attorney issued by the rector of the University, with full or partial powers of a legal entity. The branch was created on the basis of Order No. 259 of May 28, 1996 of the Ministry of Education of the Russian Federation, renamed into a branch of the state educational institution of professional higher education “Kostroma State University named after. ON THE. Nekrasov" in the city of Kirovsk, Murmansk region, on the basis of order No. 965 of 03/02/2004 of the Ministry of Education of the Russian Federation. The branch carries out its activities in accordance with the Constitution of the Russian Federation, the Law of the Russian Federation "On Education", the Law of the Russian Federation "On Higher and Postgraduate Professional Education", others federal laws state, the Charter of the State Educational Institution of Higher Professional Education “Kostroma State University named after. ON THE. Nekrasov”,_Regulations on the branch. The director of the branch is appointed by order of the rector of the University. The director of the branch is Lyudmila Viktorovna Koptyaeva. If there is a power of attorney to grant the branch the powers of a legal entity, the director of the branch represents it in all bodies, institutions, and enterprises: 1 - opens branch accounts in the bank, issues orders and gives instructions mandatory for all employees and students; 2 - disposes of the property of the branch, including concluding agreements with subsequent notification of the Academic Council of the branch; 3 - carries out the hiring and dismissal of branch personnel, deputy directors and accountants, determines their specific duties and responsibilities 4 - determines the competence, level of responsibility, volume and forms of material financial incentives for branch employees 5 - bears personal responsibility for the results of the branch’s work. The main objectives of the branch are:
Research activities
The management of the department is carried out by the head, who is elected by the Academic Council of the university for a period of up to five years and confirmed in office by the rector of the university, and bears full responsibility for the results of work within the scope of his competence. The department includes professors, associate professors, senior teachers, teaching assistants, educational and support staff. The department provides methodologically and manages educational and production programs, coursework and diploma works (projects), independent studies for students, prepares and conducts term papers, exams and tests, organizes practical training. Today the branch has the following 4 departments. The reorganization and liquidation of the branch is carried out by order of the Ministry of Education and Science of the Russian Federation in the prescribed manner. The liquidation of a branch is carried out by the liquidation commission on the grounds provided for by the Laws of the Russian Federation in the prescribed manner. 1.2 Characteristics of computer equipment 9 Intel Pent-4 computers 9 LG monitors Computer clock speed 2.4 megahertz USB model A CD-ROM CCD-40 X3H is installed on one computer RAM -256 MB 9 comps brand Sisg50-651-M 650-M652-740 9monitors Clock frequency 1700mH RAM 128 MB 7pcs HDD 30GB-40GB Operating system Wind-98 Their brand is Intel Pent-3 Clock frequency -602 mH RAM - 12 MB Hard disk - 10-20 GB Wind-98 installation 3 computers: 1 set - Intel Celeron T-frequency 667mG RAM 128 MB Hard disk - 120 GB Operating system Wind-XP Siver SAMSUNC LG flatron LCD monitor EPSH dot matrix printer 2nd ACEZ monitor 2 computer monitor AMD-k5 Clock frequency 100 mH RAM 32 MB Hard disk - 8 MB Operating system Wind-98 network version Siver –Beno Intel Pent-4 Server Clock frequency 2.66 mH RAM 256 MB Hard disk-20 MB Operating system Winolows N1 Pzo The photocopier oievelop 1300 is located 2nd LG LCD monitor AMD Duzen computer 2 green manures Scanner - Mustek Model ACCUZA Hays HD laser printer Brief list of equipment: Each department of the KSU branch is equipped with a PC and peripheral devices: Printer Xerox Multifunctional devices: Computer classes 102-201 are united into a local network for star topology communication. In the future, it is planned to combine 3 branch buildings into one network for more efficient information exchange. The branch's classes are designed to conduct practical classes in information disciplines. Computers are equipped with server and software. In practical classes, specialized packages are used, universal Programs such as: Accounting Turbo Pockal Mat Kat As well as a text editor, graphics processor, spreadsheet processor and DBMS Computer classes are equipped with legal reference systems: Consultant + Guarantor There is Internet access. Each computer is equipped with a parallel connection that protects against unauthorized access. The general name for software designed for creating, editing and formatting simple and complex text documents, word processors. Currently, the most widely used word processor is Microsoft Word. Microsoft Word processor working window Working window of the Microsoft Word 2000 processor Its main controls: menu bar, toolbar, work field and status bar, including indicators. Starting with the Microsoft Word 95 processor, the toolbar is customizable. Document display modes Starting from the sixth Microsoft versions Word supports several document presentation modes. In normal mode, only the content of the document is presented without requisite design elements that relate not to the text, but to the printed pages (headers, footers, subpage footnotes, etc.). This mode is convenient in the early stages of document development (text input, editing, reviewing), as well as in all cases when the content of the document is of higher importance than its external presentation. In this mode, operations with large documents are faster, which is important when working on low-performance computers. In mode Web document The screen representation does not match the printed one. This is a departure from the WYSIWYG principle, but it is typical for electronic publishing on the World Wide Web because it is not known in advance which viewer or equipment the document will be displayed on. The concept of a printed page is meaningless for electronic documents, so assigned page settings are not taken into account, and formatting of the document on screen is relative. Electronic publications are developed in this mode. In markup mode, the screen representation of the document fully corresponds to the printed one, right down to the assigned parameters of the printed page. This mode is convenient for most work related to formatting text intended for printing. In Outline view, you can only display document headings. The mode is useful in cases where the development of a document begins with the creation of a content plan. If the document is more than 5-7 printed pages in size, you should always start by creating a primary outline. The mode differs in that when it is turned on, the auxiliary Structure panel automatically opens on the toolbar, the controls of which allow you to edit the structure of the document. Selecting one of the four above document presentation modes is done using the command buttons located in the lower left corner of the application window, or using the View menu commands. A special view (fifth mode) is also available through the View menu. A document layout in which the application window has two working panels. The left panel shows the structure of the document, and the right panel shows the document itself. This mode, which combines the advantages of the markup mode and the structure mode, is useful when navigating through a voluminous document - it is convenient to use not when creating, but when viewing documents with a complex structure. Two more document presentation modes are available through the File menu, used for previewing. For electronic documents, use the File command. Preview of the Web page, and for printed documents - the Preview file. In the first case, the created document is displayed as a Web page in the browser window registered by the operating system as the default one (it is desirable that this be Microsoft browser Internet Explorer 5.0). In the second case, the document is presented in a special window Techniques for working with texts in the Microsoft Word processor Basic techniques for working with texts in the Microsoft Word word processor include the following:
1.2.2
MicrosoftExcel– editor of a set of formulas, plotting. Towards significant achievements in new version Excel programs can be attributed to the emergence of three-dimensional documents (notepads). Establishing links between files and tables has been greatly simplified compared to previous versions. Context menus have been significantly expanded, and additional software tools make it easier to solve complex application problems. It is also worth mentioning the various assistants (Assistants), which help the user set functions and give recommendations if there is a simpler method for solving the current task. The Excel program has a built-in convenient help subsystem, which is ready to issue the necessary help at any time. The innovations described so far relate mainly to ease of use and quick mastery of the program. One of the most important functional extensions of the program, intended for professionals, is the Visual Basic (VBA) programming environment built into Excel for solving applied problems. Thanks to VBA, Microsoft was able to not only expand the capabilities of the Excel 4.0 macro language, but also introduce a new level of application programming, since VBA allows you to create full-fledged application packages that, in their functions, go far beyond spreadsheet processing. In addition, the following important innovations of Excel 5.0 should be mentioned: File manager, which provides detailed information about all files; Dialog boxes-registers; Separate icon for formatting; The appearance of the Drag&Plot mechanism, designed to quickly activate diagrams. All table data is recorded in so-called cells, which are located at the intersection of the rows and columns of the table. By default, the contents of a cell are presented by Excel in a standard format, which is installed when the program starts. For example, numbers and texts are set to a specific font type and size. Excel has context menus that are called up with the right mouse button when a certain area of the table is marked. These menus contain many table processing and formatting directives. The ability to use formulas and functions is one of the most important features of a spreadsheet program. This, in particular, allows for statistical analysis numerical values in the table. The text of a formula that is entered into a table cell must begin with an equal sign so that Excel can distinguish the formula from text. After the equal sign, a mathematical expression containing arguments, arithmetic operations and functions is written into the cell. Numbers and cell addresses are usually used as arguments in the formula. The following symbols can be used to denote arithmetic operations: + (addition); - (subtraction); * (multiplication); / (division). The formula may contain references to cells that are located on another worksheet or even in a table in another file. Once entered, the formula can be modified at any time. The built-in Formula Manager helps the user find an error or incorrect link in a large table. In addition, Excel allows you to work with complex formulas containing several operations. For clarity, you can turn on text mode, then Excel will display in the cell not the result of the formula calculation, but the formula itself. Graphic charts enliven the dry columns of numbers in a table, which is why already in early versions of Excel the ability to create charts was provided. On the fifth Excel version A new Chart Builder is included that allows you to create "presentation quality" charts. A beautiful 3D diagram not only pleases the eye, but also improves the quality of the document. MS Excel 5.0 has introduced a new type of three-dimensional charts - the so-called donut charts, which complement the surface and grid three-dimensional charts of the fourth version. It is fashionable to place the diagram next to the table or place it on a separate worksheet. The Chart Builder is one of the most powerful tools in Excel. Constructing a diagram with its help is carried out in several steps. The designer is given the source area of the table, the type of chart, the labels and colors to use. The main panel has an icon for calling the Chart Designer. To perform tabular calculations, you need formulas. Because some formulas and their combinations are very common, Excel offers more than 200 pre-programmed formulas called functions. All functions are divided into categories to make them easier to navigate. The built-in Function Builder helps you use functions correctly at all stages of work. It allows you to build and calculate most functions in two steps. The program has an alphabetically organized full list all functions, in which you can easily find a function if you know its name; otherwise, you should search by category. Many features vary very slightly, so when searching by category it is useful to use brief descriptions functions that the Function Builder offers. A function operates on some data called its arguments. A function argument can occupy a single cell or be placed in an entire group of cells. The function constructor provides assistance in specifying any type of arguments. Data exchange allows Excel users to import objects from other applications into their tables and transfer (export) their tables for embedding in other objects. 1.2.3
MicrosoftAccess– editor for creating databases.
Creating tables. Working with any objects begins with the Database window. Its left panel contains controls for calling all seven types of program objects. Creating tables begins by selecting the Tables control. The right panel provides a list of tables already included in the database and provides controls for creating a new table. To create a table manually, use the Create Table icon in Design view. The lower part of the form contains a list of properties of the field highlighted in the upper part. Some of the properties are already set by default. Field properties are optional. They can be adjusted as desired, or left untouched. When creating a table, it is advisable (though not required) to specify a key field. This will help later when organizing connections between tables. To set a key field, just right-click on its name and select Key Field in the context menu that opens. We said above that if a primary key is needed to relate to other tables, but none of the fields is unique, then a primary key can be created based on two (or more fields). This operation is performed in exactly the same way, via context menu, you just need to be able to select several fields at once Having finished creating the table structure, close the form (the system prompts you to save the table), after which you give the table a name, and from that moment it is available among other tables in the main Database window. From there you can open it if necessary. The created table is opened in the Database window by double-clicking on its icon. The new table has no records - only column names that characterize the structure of the table. Filling the table with data is done in the usual manner. At the bottom of the table there is a Transition Button Panel. Its controls are convenient to use when navigating through a table that has a large number of records. For beginners Microsoft users Access suffers from the fact that data doesn't always fit into table cells. The width of columns can be controlled by dragging their borders. It is convenient to use automatic formatting of columns “by content”. To do this, place the mouse pointer on the border between the columns (in the column header line), wait until the pointer changes shape, and double-click After filling the table with data, there is no need to save it - everything is saved automatically. However, if, while working with a table, you edited its layout (for example, the width of the columns changed), the DBMS will ask you to confirm saving these changes. If there is a need to change the structure of the table (the composition of the fields or their properties), the table must be opened in Design mode. To do this, select it in the Database window and click on the Design button. Creating inter-table relationships. If the database structure is thought out in advance, and the relationships between tables are outlined, then creating relational relationships between tables is very simple. All necessary work takes place in a special Data Schema window and is performed using the mouse. The Data Schema window is opened with a button on the toolbar or with a command. 1.2.4
MicrosoftPowerPoint– graphic editor (design of presentations). Creating presentations The process of creating a presentation in Microsoft PowerPoint consists of such actions as choosing a general design, adding new slides and their content, selecting markings slides, changing the design of the slides if necessary, changing color scheme, the use of various design templates and creating effects such as slide show animation effects. The information below is about the tools available to start this process. Task pane Creating a Presentation in Microsoft PowerPoint provides the following number of options for creating a new presentation.
Create a presentation using blank slides Create a presentation based on suggested content
Following the steps below will create a copy of your existing presentation, which will allow you to make changes to the design and content of the copy of the presentation without changing the original.
Stocks and bods market. General information: In a modern market economy, the securities market occupies a special and very important place. The history of the securities market goes back several centuries. 400 years ago, in 1592, a list of prices for securities sold on the local stock exchange was first published in Antwerp. This year is considered the year of the birth of stock exchanges as special organizations involved in the purchase and sale of securities. In the regulated economy of the Soviet period, there were simply no securities. Only bonds of government loans were in circulation, which can be called a security only with great stretch due to the forced nature of the distribution of most issues of these loans and the lack of free circulation. Securities - are documents that have legal force, drawn up in a certain form and giving their owner a unilateral standardized set of rights in relation to the persons who issued these documents, the ability to transfer these documents, subject to pre-agreed conditions, but without the consent of the issuers, to another person together with the whole range of rights contained in them. The peculiarities of the formation of the Russian securities market include the issue of shares during the transformation of state-owned enterprises into joint-stock companies in the process of privatization. In Russia, mass privatization led to the appearance of a huge number of securities in circulation, but this way of expanding the stock market is not typical for world experience. Especially in countries with developed market economies, privatized enterprises are already joint-stock companies, the controlling stake of which belonged to the state before privatization. Another feature of the formation of the securities market in Russia was the issue by federal authorities of part of government securities not to attract funds, but with the aim of giving a more civilized market form to government debts. It was for this purpose that bonds of the Internal State Foreign Currency Loan, Treasury bills, rural bonds were issued, and here, with reservations, one can also include the Privatization Checks of the Russian Federation of the 1993 model. As with shares of privatized enterprises, these government securities laid the foundations for the modern Russian securities market. In general, the securities market is a complex system with its own structure. Organizationally, the securities market includes several elements:
Types of securities: 1. bearer securities are securities that do not indicate the name of the owner. Most often they are issued in small denominations and are intended for investment by a wide range of people. 2. registered securities - the owner’s rights to such a security must be confirmed by entering the owner’s name in the text of the security itself and in the register maintained by the issuer. Such securities can be sold on the secondary market, but in order to register the transfer of ownership it is necessary to register the transactions in the register, which complicates the circulation of registered securities compared to bearer ones. Most securities circulating in Russia are registered. 3. order securities – the rights of the owner of order securities are confirmed by transfer notes in the text of the paper and by presentation of the paper itself. This category primarily includes bills of exchange and checks. The practice of attracting financial resources to joint-stock companies has developed a large number of types of shares that satisfy a wide variety of consumer needs. The nominal price only shows what part of the value of the authorized capital in absolute terms is accounted for by a given share. Beyond this, at par value, only a minimum of information can be obtained, namely, if the par value of an ordinary share is divided by the size of the authorized capital of the enterprise, reduced by the volume of issued preferred shares, then the minimum share of votes per share at a meeting of shareholders will be obtained, and the share of profit that will be paid on this share from the total amount allocated for dividends on ordinary shares. Bonds – this is the issuer’s obligation to pay certain amounts of money to the owner of this security within a certain period of time. Due to their debt-based nature, bonds are safer investments than stocks; being an analogue of a loan, they are “senior” securities in relation to shares, that is, they give a preferential right when paying income or returning invested funds in the event of bankruptcy or liquidation of the issuer. The higher reliability of bonds makes them popular among investors, and bonds account for more than half of the turnover of most of the world's largest stock markets. According to the status of the issuer, foreign issuers of bonds are sometimes classified into a separate category, which are also divided into private companies and government agencies. Derivatives – An option is an obligation, written in the form of a security, conveying the right to buy or sell another security at a specified price up to or at a specified future payment. Warrant is a security that gives the right to purchase other securities during their initial placement at a certain price and is sold by the issuer of these securities. Certificates of Deposit and Savings – This is a bank certificate of deposit of funds, giving the right to receive the deposit and the agreed interest. In fact, certificates of deposit and savings certificates are a type of bank time deposits that can be resold. The attractiveness of certificates of deposit for Russian investors is due to the peculiarities of tax legislation, according to which income from simple deposits of legal entities is subject to taxation at the income tax rate, and income from certificates of deposit is taxed as income from securities, the tax rate for which is much lower. Bills – it is a promissory note drawn up in accordance with established laws, and giving its owner an unconditional right to claim a specified amount upon the expiration of a specified period. To characterize the turnover of bills of exchange, you should become familiar with the special terminology used in this sector of the securities market:
Other securities – Among other securities that are important for the Russian stock market, we can highlight units of mutual investment funds and depository certificates. Securities include:
As a result of educational and technological (computer) practice, I studied and mastered the following programs:
Personally, as a student, this will help me in writing coursework, practical work, as well as when writing diploma projects, namely, to feel more free in the above programs. Conclusion During the practice the following were completed:
Bibliography
1. Introduction In our age of computer technology, not a single company can do without the use of computers. And if there are several computers, then, as a rule, they are combined into a local area network (LAN). A computer network is a system of interconnected computers, as well as possibly other devices called nodes (workstations) of the network. All computers on the network are connected to each other and can exchange information. As a result of connecting computers into a network, the following opportunities arise: increasing transmission speed information messages, rapid exchange of information between users, expanding the list of services provided to users by combining significant computing power in a network with a wide range of different software and peripheral equipment. Use of distributed resources (printers, scanners, CD-ROMs, etc.), availability of structured information and effective search for the necessary data. Networks provide enormous benefits that are unattainable when using computers separately. Among them: sharing of processor resources. By sharing processor resources, it is possible to use computing power for simultaneous data processing by all stations included in the network. Data separation. Data sharing makes it possible to manage databases from any workstation that needs information. Internet sharing. A LAN allows you to provide access to the Internet to all your clients using just one access channel. Resource sharing. A LAN allows you to economically use expensive resources (printers, plotters, etc.) and access them from all connected workstations. Multimedia capabilities. Modern high-speed technologies make it possible to transmit audio and video information in real time, which allows you to conduct video conferences and communicate over the network without leaving your workplace. Nowadays, not a single large enterprise can do without a LAN. The purpose of this industrial professional practice is to study the features of operation and Maintenance computer equipment and computer networks. Currently, the enterprise network continues to develop. New computers are added to workplaces, as a result of which the number of requests to servers increases. Therefore, the main direction of network modernization is replacing servers with more modern ones. The first steps were taken at the beginning of 2004, when one of the mail servers and the TKIIP information concentrator were replaced. Also, most of the jobs at hub stations require modernization. At the enterprise in 1998, a bus topology was used to build the network, i.e. all computers were connected in series one after another using a cable system. In this case, the Ethernet standard technology was used. Ethernet is the most common local area network standard. Ethernet usually refers to any of the variants of this technology: Ethernet, Fast Ethernet, Gigabit Ethernet. All types of Ethernet standards use the same method of separating the data transmission medium - the CSMA/CD method - a multiple access method with carrier sensing and collision detection. In a narrower sense, Ethernet is a network standard with a data transfer rate of 10 Mbit/s. The historical first networks of Ethernet technology were created on coaxial cable. Subsequently, other physical layer specifications for this standard were defined. Physical specifications of Ethernet technology today include data transmission media: 10 Base-5 is a coaxial cable with a diameter of 0.5 inches, called “thick” coax. Has a characteristic impedance of 50 Ohms. Maximum segment length 500 meters without repeaters; 10 Base-2 is a coaxial cable with a diameter of 0.25 inches, called “thin” coax. Has a characteristic impedance of 50 Ohms. The maximum segment length is 185 meters without repeaters; 10 Base-T - cable based on unshielded twisted pair (UTP) category 3. Forms a star topology based on a hub. The distance between the hub and the end node is no more than 100 meters; 10 Base-F – fiber optic cable. The topology is similar to that of the 10 Base-T standard. There are several variants of this specification - FOIRL (distance up to 1000 meters), 10 Base-FL (up to 2000 meters), 10 Base-FB (up to 2000 meters). The number 10 in these names indicates the bit rate of data transmission of these standards - 10 Mbit/s. An important phenomenon in Ethernet networks is collision - a situation when two stations simultaneously try to transmit a data frame over a common medium. This is a consequence of the random access method adopted. But over time, the number of computers increased, and data transfer via the bus became impossible due to loss of speed. In this case, the enterprise decided to use the STAR network topology. In this case, there is a server to which all computers participating in the local connection are directly connected. computer network. To build the network, “Fast Ethernet” technology was selected and applied, and “Gigabit Ethernet” is currently being used. Fast Ethernet: In 1995, the IEEE 802.3 committee adopted the Fast Ethernet specification as the 802.3u standard, which is not a standalone standard but an addition to the existing 802.3 standard. The MAC and LLC layers in Fast Ethernet remain exactly the same as in Ethernet. The access method also remains the old one - CSMA/CD. This ensured continuity and consistency between the 10 Mbit/s and 100 Mbit/s networks. All the differences between Fast Ethernet and Ethernet technologies are concentrated at the physical layer. The more complex structure of the technology's physical layer is due to the fact that it uses three types of cabling systems: Fiber optic multimode cable, two fibers are used; Coaxial cable is not included in the permitted data transmission media of Fast Ethernet technology. Networks based on this technology always have a hierarchical tree structure built on hubs. The network diameter is reduced to 200 m (for a hub-based network). The speed, in comparison with Ethernet, is increased 10 times by reducing the inter-frame delay. The technology operates in full duplex mode. The 802.3u standard established 3 different specifications for the Fast Ethernet physical layer, giving them the following names: 100Base-TX for two-pair cable on unshielded twisted pair UTP category 5 or shielded twisted pair STP type 1. Maximum segment length is 100 m; 100Base-T4 for four-pair cable on unshielded twisted pair UTP categories 3,4 or 5. Maximum segment length - 100 m; 100Base-FX for multimode fiber optic cable, uses two fibers. The maximum segment length is 412 m (half duplex), 2 km (full duplex). Gigabit Ethernet: Fast enough after Fast products hit the market Ethernet network integrators and administrators felt certain limitations when building corporate networks. In many cases, servers connected via a 100-megabit channel overloaded network backbones. There was a need for the next level of the speed hierarchy. Therefore, in June 1995, the IEEE High Speed Technology Research Group was assigned to consider the possibility of developing an Ethernet standard with an even higher bit rate. The Category 5 twisted pair standard was finally adopted in 1999. Gigabit Ethernet transfer speed is 1000 Mbps. The developers have maintained a large degree of continuity with Ethernet and Fast Ethernet technologies: the same frame formats operate in half-duplex and full-duplex modes, supporting the same CSMA/CD access method on a shared medium with minimal changes. In the summer of 1998, the 802.3z standard was adopted, which defines the use of three types of cable as a physical medium: multimode fiber optic (distance up to 500 m), single-mode fiber optic (distance up to 5000 m) and twin coaxial (twin ax), through which data is transmitted over two shielded copper conductors at a distance of up to 25 meters. Special working group 802.3ab has developed a variant of Gigabit Ethernet on UTP category 5. To provide speeds of 1000 Mbit/s, simultaneous data transmission is used over four unshielded twisted pairs, speed 250 Mbit/s. 4. Network hardwareWorkstations are any computers that access resources stored on a server via a local network.basically all enterprise workstations have the following configuration: Intel Pentium III 1.3 GHz processor; RAM 256 Mb; LAN 10/100Mb/s; IDE 40Gb hard drive. Some workstations have a CD-ROM drive, sound card and speakers, HP 1200 printers. 4.3 SwitchesA switch is a multiport link-layer device that “learns” MAC addresses and stores them in an internal lookup table. A temporary switched connection is created between the sender and the intended recipient of the frame, through which the frame is transmitted.To connect computers into a network, 3Com Super Stack Switch 4900, 4924, 4400 SE and 4-port 1000BASE-SX optical modules are used to connect backbone channels. Central distribution 3Com Super Stack Switch 4900, 4900SX: IEEE 802.1р standard, 1000Base-TX; Capacity 23 million. packets/s (24 ports); Access method CSMA/CD; Size 6.6*44*37 (cm), weight 6.5kg; Permissible ambient humidity 10%~90%; 3Com Super Stack 3 Switch 4400SE IEEE 802.3ad standard, 1000Base-SX; Form a stack of up to 192 ports 10/100Mbit/s; Throughput 6.6 million packets/s (24 ports); Physical media UTP category 5e; Power supply 100-240V (50-60Hz); Size 6.6*44*41 (cm), weight 6.3kg; Permissible temperature environment 00C~40C; Permissible ambient humidity 10%~90%. Uses non-blocking Gigabit Ethernet switching at the fastest possible speed, using XRN technology can increase performance up to 48 Gbps. Layer 3 switching is also used, supporting unicast IP routing and OSPF protocols. RIP/RIPv2 and CIDR availability of UDP traffic control function. Uses advanced security capabilities, RADIUS client support, and support for Routed Access Control Lists to provide automated user access to network resources. Supports 3Com Gigabit Multilayer Switching (GMS) software and provides advanced Layer 2 switching. They have advanced network management functions. The 3Com Network Supervisor software (simplifies network administration tasks) detects devices connected to the network, displays their status in a graphical diagram and controls them. 4.4 Network adapters Network adapters are designed to receive and transmit data on a network. Mainly used on department computers network cards D-Link 530TX 10/100 Mbit/s. Supports 32-bit PCI bus in Lokal Bus mode, auto-sensing Nway, complies with IEEE 802.3u/ 8702.3 standard, supports Plug and Play installation, ACPI, WOL, as well as power management. 4.5 Modems Modem is a functional device that provides modulation and demodulation of signals; device that converts digital signals into analog form and back to transmit them over communication lines analog type. Characteristics of external ADSL modem: Reception speed 8 Mb/s and transmission up to 1 Mb/s; RJ-11 connector for connecting to the line; Ethernet interface 10/100Mb/s with auto cable detection; Work in bridge and router modes, routing using a multi-address policy; Compliance with G.PMT(G.992.1) standards; Service quality management (UBR/CBR/VBR); Configuration via WEB interface or Telnet; Administration and SNMP; System requirements; PC with Ethernet interface 10/100 Mb/s; CD drive or DVD discs; Telephone line with ADSL access service from an Internet provider. 4.6 Cabling system No less important in the design of a local network is the choice of cable subsystem, since a reliable LAN provides reliable connections. In other words, all connections in the network must be made with high quality, unreliable contacts and other physical damage. This is given such important attention because finding a broken or damaged connection in a faulty network is still a very time-consuming task. The answer to the high requirements for the quality of the cabling system has become structured cabling systems, which are a set of switching elements (cables, connectors, connectors, cross-connect panels and cabinets), as well as a technique for their joint use, which allows you to create regular, easily expandable connection structures in computer networks . Versatility; Increased service life; Reliability. Review of cable equipment. twisted pair(UTP/STP, unshielded/shielded twisted pair) is currently the most common signal transmission medium in local networks. UTP/STP cables are used in Ethernet, Token Ring and ARCnet networks. They vary by category (based on bandwidth) and conductor type (flexible or solid). A Category 5 cable usually contains eight conductors twisted in pairs (that is, four pairs). All cables consist of 4 pairs (two for file transfer, the other two for voice transfer). RJ-45 plugs and sockets are used to connect cables to equipment. Category 6 cables have also appeared, with a frequency of up to 200 MHz, and category 7, with a frequency of up to 600 MHz, which must be shielded. A structured cabling system built on Category 5 twisted pair cable is very flexible in use. Her idea is as follows. A structured cabling system is built hierarchically, with a main trunk and numerous branches from it. A typical hierarchical structure of a structured cabling system includes: Horizontal subsystems (within a floor); Vertical subsystems (inside the building); Campus subsystem (within one territory with several buildings). Using a structured cabling system instead of haphazardly laid cables gives a business many benefits: Versatility; Increased service life; Reducing the cost of adding new users and changing their placements; Possibility of easy network expansion; Providing more efficient service; Reliability. The horizontal subsystem is characterized by a large number of cable branches, since it must be routed to each user outlet. Therefore, the cable used in horizontal wiring is subject to increased requirements for the convenience of making branches, as well as the convenience of its installation in premises. When choosing a cable, the following characteristics are taken into account: bandwidth, distance, physical security, electromagnetic immunity, cost. The horizontal subsystem, that is, the floor subsystem, can be divided into three parts: The subscriber part consists of RJ-45 sockets connected by a patch cord; The stationary part is a patch cord that connects the sockets to the cabinet with network equipment; The patch part is the patch cord between the switch and the sockets on the patch panel. The vertical subsystem, the cable that connects the floors of a building, must transmit data over longer distances and at higher speeds compared to the horizontal subsystem cable. It consists of longer sections of cable, the number of branches is much less than in the horizontal subsystem. Optical fiber, as its name suggests, transmits signals using pulses of light. Semiconductor lasers and LEDs are used as light sources. Optical fiber is divided into single-mode and multimode. Single-mode fiber is very thin, its diameter is about 10 microns. Thanks to this, the light pulse passing through the fiber is less often reflected from its inner surface, which ensures less attenuation. Accordingly, single-mode fiber provides longer range without the use of repeaters. The theoretical throughput of single-mode fiber is 10 Gbps. Its main disadvantages are high cost and high complexity of installation. Single-mode fiber is mainly used in telephony. Multimode fiber has a larger diameter - 50 or 62.5 microns. This type of optical fiber is most often used in computer networks. The higher attenuation in multimode fiber is due to the higher dispersion of light in it, due to which its throughput is significantly lower - theoretically it is 2.5 Gbps. All active switching equipment is located in special cabinets made of transparent plastic, which allows you to clearly see all the equipment. Patch panels, converters, switches, hubs, etc. are used. In departments, wires are mounted on the walls using special boxes or on the ceiling under suspended ceilings. Everything is organized simply, conveniently and neatly. Special connectors are used to connect the optical cable to active equipment. 5. Network software and network administrationThe wide variety of types of computers used in computer networks entails a variety of operating systems: for workstations, for department-level network servers and enterprise-level servers as a whole. They may have different performance and functionality requirements, and it is desirable that they have compatibility properties that would allow different operating systems to work together. Network operating systems can be divided into two groups: department-scale and enterprise-scale. Departmental or workgroup operating systems provide a range of network services, including file, application and printer sharing. They must also provide fault tolerance properties, for example, work with RAID arrays, support cluster architectures. Departmental network operating systems are usually easier to install and manage than enterprise network operating systems. They have less functionality, less data protection, weaker interoperability with other types of networks, and poorer performance. An enterprise-scale network operating system, first of all, must have the basic properties of any enterprise products, including: Scalability, that is, the ability to work equally well in a wide range of different quantitative network characteristics; Compatibility with other products, that is, the ability to work in a complex heterogeneous Internet environment in a plug-and-play mode. The criteria for choosing an enterprise-scale OS are the following characteristics: Seamless support for multi-server network, high efficiency of file operations; Possibility of effective integration with other operating systems, availability of a centralized scalable help desk, good development prospects; Effective work of remote users, various services: file service, print service, data security and fault tolerance, data archiving, messaging service, various databases and others; A variety of software and hardware host platforms: IBM SNA, DEC NSA, UNIX; Various transport protocols: TCP/IP, IPX/SPX, NetBIOS, Appletalk; Supports a variety of end user operating systems: DOS, UNIX, OS/2, Mac; Support for network equipment of Ethernet, Token Ring, FDDI, ARCnet standards; Availability of popular application interfaces and mechanisms for calling remote procedures RPC; Ability to interact with the network monitoring and management system, support for SNMP network management standards. Of course, none of the existing network OSs fully meets the listed requirements, so the choice of a network OS is usually made taking into account the production situation and experience. One of the main tasks at the Lepse OJSC enterprise is information protection. Information security measures include: Passwords installed on computers; Antivirus programs; Power protection on servers and some workstations. The company has created the 1st department, which is responsible for the archive of classified information. Before accepting a new employee for work or practice (who will directly work with a computer and data), the person must be familiar with the information security instructions. He will also need to obtain a certificate from the first department. Information stored directly on computers is protected by restricting access for administrators and guests, each of whom has a separate login and password. User groups are created with certain rights and authorities (for example: user) to access network resources. That is, an employee with a certain position is granted certain access rights and a volume of information related specifically to his activities. Thus, the more rights, the more information the user has. The administrator can carry out all actions: enter new data into the database, delete records from the database, carry out various settings of systems and programs. A ordinary users can only perform certain actions. For example, viewing and searching for the necessary information. Protection against viruses can be ensured using common anti-virus programs such as Kaspersky Anti-Virus, Dr.Web and McAfee others. The company primarily uses McAfee. In order to protect information from viruses and from its leakage, work on the Internet occurs on separate computers that are not connected to the network. 7. Power protection devices To protect servers, as well as a number of simple workstations, from power surges, enterprises use uninterruptible power supplies. UPS (Uninterruptible Power Supply) uninterruptible power supplies provide all levels of computer power supply protection. They are also the most expensive of all power protection devices. While backup power supplies (BPS) provide power to the computer only in the event of a power outage, uninterruptible power supplies (UPS) provide a continuous supply of modulated direct current from the battery to the computer. The alternating current of the power network is not supplied directly to the computer's power supply; it only constantly charges the battery of the uninterruptible power supply unit. As a result, the computer is isolated from any AC voltage anomalies. Like a backup power supply, an uninterruptible power supply can only keep the computer running for a certain period of time (depending on the load), which allows the user to save the results of their work and shut down the operating system in the normal way. The uninterruptible power supply supplies voltage to the computer continuously, so when using it there is no problem with the duration of switching to offline mode battery operation. High-quality uninterruptible power supplies provide uninterrupted power to the computer, as well as correction of voltage dips and protection against pulses and peaks that occur in the alternating current network. The enterprise uses sources of uninterruptible APC power supply Smart-UPS 5000VA 230V. Technical characteristics of uninterruptible power supplies APC Smart-UPS 5000VA 230V are given in Table 1. Table 1 - specifications uninterruptible power supplies APC Smart-UPS 5000VA 230V.
8. Feasibility study of the network The main factor in the feasibility study of a network is the total cost of creating a LAN. The total costs indicator consists of the following parts: LAN development costs; Costs of equipment and materials; Marketing research costs. The total costs of creating a LAN are determined by formula (1): Total costs for creating a LAN; LAN development costs; Taxes included in the costs of creating a LAN; Costs for equipment and materials (calculated when designing a LAN); The costs of marketing research can be taken in the amount of 10-20% of. The amount of taxes is calculated using formula (2):
General wage fund for workers involved in the creation of the LAN; The general tax rate (in addition to transport), including in the costs of creating a LAN, can be taken at 10%. The total wage fund for workers participating in the creation of the LAN is determined by formula (3):
Time of participation of a specialist of a certain qualification in creating a LAN (data taken from Table 3); Number of specialists with certain qualifications; The monthly salary of the employee in accordance with his category or tariff category of the Unified Labor System of the budget sector; Shift duration (8 hours); Average number of working days in a month (21 days); The bonus provided for employees is 20-25% of; Payments according to the regional coefficient (Kirov 15% of (+P)). The costs of developing a LAN are calculated using formula (4): Costs for developing the project and documentation; Installation and installation costs; Commissioning costs; Other costs associated with the creation of a LAN (studying the assignment, literature, patents, carrying out economic calculations, etc.); The costs of developing the project and documentation are determined by formula (5): Costs of paying wages to employees involved in the development of the LAN; Bonus for employees involved in the development of the project and documentation; Regional coefficient for employees involved in the development of the project and documentation (15%); General rate of contributions for social needs (26%); The wage fund for workers involved in the development of the project and documentation (includes wage bonus and payments according to the regional coefficient); Setup costs for an organization that creates a LAN. They can be accepted in the amount of 100-200% of. Other costs for creating a LAN are 15-20% of the costs, and are calculated using formula (7): The costs of materials and equipment are calculated when designing the LAN, and their price is taken from the LAN design. The overall cost estimate is presented in Table 2. Table 2. The “other” line includes: sockets, mounting cabinets, brackets, network adapters, network installation work, etc. As a result, the total cost of building the network was about 86 million rubles. The salaries of those involved in the development and construction of the network are not indicated, since the plant’s network was not built immediately, but was modified as needed over several years. Therefore, it is almost impossible to calculate the salaries of people involved in the development and construction of the network. 9. Measures for preventive maintenance of VT equipment Preventive maintenance of computers can be divided into: Emergency; Scheduled (monthly, annual); Preventive maintenance of copiers. Emergency maintenance is carried out when the SVT fails. Maintenance is carried out by a specialist in servicing VT equipment. It includes the following types of work: Diagnostics of computer hardware and software; Elimination of hardware (replacing a failed unit with a serviceable one) or software malfunction (reinstalling the OS, reinstalling programs). Monthly preventative maintenance includes: Removing dust from the external parts of the PC (with the power off); Visual inspection of cables: power supply, monitor interface cables, keyboard, mouse, printer, LAN cable; Cleaning the magnetic heads of floppy drives using a cleaning floppy disk; Prevention of the keyboard, monitor, processor and other devices (checking using special test programs and external inspection). During the annual preventive maintenance of equipment, the following actions are performed: Performing a visual inspection of the computer; Checking the functionality of the cooling system of the processor, hard drive, video card; Cleaning the monitor, keyboard, mouse and case from dust with cleaning products; Cleaning the drive and optical drive special cleaning floppy disks and optical disks; Defragmentation of hard disk; Checking hard disk for viruses antivirus programs; Checking the compliance of programs installed on the computer with the programs recorded in the data sheet. Maintenance of copiers is also carried out periodically. TO includes: Cleaning the outside of the printer from dust and waste from the printing process; Cleaning the inside of the printer (cleaning the interior mirror with a cleaning brush, wiping the rollers with alcohol); Checking print quality using a test. If noise occurs during computer operation or when the PC or printer gets very hot, clean the cooling systems: Cleaning from dust using a brush or piece of cloth (outside and inside); Removing foreign objects that got into the fan/radiator during operation; Fan axis lubrication. 10. Diagnostic tools and maintenance 10.1 Software and hardware diagnostic tools All methods for troubleshooting and diagnosing devices can be divided into two main groups: Hardware method; Software method. Diagnostic software includes various programs and utilities that can be used to check your computer: MHDD 4.6 is designed to test a hard drive for logical and hardware errors; MemoryTest is designed for memory testing; Actra1.40 is a utility that collects all information about the computer, as well as all information about the software that is installed on the computer. The hardware method includes external inspection, checking the correct connection using special devices - testers. The SLT3 (UTP) and SLT3S (UTP/STP/FTP) testers, shown in Figure 3, are designed to test copper cable.
Figure 3 - Testers SLT3 (UTP) - light, small sizes the testers shown in Figure 3 a consist of 2 parts (master and remote), have built-in 3 RJ45 sockets for testing, respectively 3 methods of cable termination (sequences) USOC, 568A, 568B For ease of transportation, both parts of the tester are connected to each other (placed in a case, attached to the installer’s belt), while the batteries are turned off, thereby extending their service life. The tester is able to detect short circuit, line break and inconsistency of this sequence (cores or pairs are upside down). LED diodes signal us about all these errors in a certain way. To measure the attenuation of optical lines, it is recommended to use a tester type FLT4, shown in Figure 3 b. The tester consists of 2 parts: light signal source (FLT4-S) and receiver optical power meter (FLT4-M). The light source is very easy to maintain. The only manually adjustable parameter is the wavelength of the emitted signal (850 nm or 1300 nm). The source has a switch, which also signals us about the need to replace the batteries (one power source with voltage in an EV of the Krone type). The receiver is equipped with a switch, a button for setting the ratio level (zeroing the tester when the “reference” cord is turned on), a button for selecting the wavelength, and a button for selecting the measurement option: attenuation or optical power. The measurement results are displayed on the LCD screen. 10.2 Tools and devices There are special tools that allow you to identify problems and fix them. These include: A simple set of tools for disassembly and assembly. Required for basic PC maintenance at the level of boards and components: screwdrivers (star-shaped, simple), tweezers, device for extracting microcircuits, pliers, flashlight, protective kit for removing electrostatic voltage, tools for minor repairs (pliers, file); Diagnostic devices and programs for testing PC components: boot disks or floppy disks, self-test board to display POST diagnostic codes when any errors are detected; Instruments for measuring voltage and resistance: digital multimeter, logic probes, single pulse generator for testing network circuits, for forcing a pulse with a duration of 1.5 to 10 μs into the circuit, network socket tester for testing an electrical outlet. Chemicals: solution for wiping contacts, a spray bottle with coolant, a can of compressed gas for cleaning PC parts; Special available tools; Test connectors for checking serial and parallel ports, memory testing devices, scanner for network cables; Markers, pens, notepads; Spare parts, fasteners. 10.3 Troubleshooting methods Troubleshooting of any node or block of a computer can be done by two main methods, such as external inspection and testing of individual blocks. External inspection includes: Checking the correct connection of computer blocks to each other; Checking cables and connectors and replacing if necessary; Checking microcircuits for burnt contacts. Testing of individual blocks includes: Checking computer units with diagnostic programs; Checking computer units using hardware diagnostic tools. If an error or any malfunction is found, it must be eliminated. And if the fault cannot be eliminated, it needs to be replaced faulty unit computer is working properly. There is also a program of preventive measures, which includes two types of measures: Passive prevention – measures aimed at protecting the PC from external influences: creation of conditions, placement, use of surge protectors, uninterruptible power supplies, proper heat removal, exclusion of sunlight, grounding; Active prevention - performing operations aimed at prolonging the life of trouble-free operation PC: PC cleaning, performing fan and CPU heat dissipation operations, scanning hard drive and removing unnecessary information, periodically performing PC monitoring. 11. Ensuring conditions for the safe operation and repair of VT equipment It is prohibited when the power is on: Move computer blocks, connect and separate them; Connect and disconnect interface cables for keyboard, mouse, monitor, printer; Place floppy disks, papers, plates, cups, rags and other items on the computer; If it is necessary to move the PC, call specialists from the system and technical support department. The movement of computers and devices connected to them by PC users is strictly prohibited. It is prohibited to eat at workplaces equipped with a PC. If any malfunctions are detected, contact specialists from the relevant inspection departments. When repairing VT equipment, the following rules must be observed: Disconnect your computer from the network; After opening the case, you need to remove the static voltage; Never place boards on a conductive metal surface. Conclusion During industrial and professional practice at Lepse OJSC, the enterprise network, its structure, network operating system, cable system, cable and switching equipment, and network software were studied. Knowledge was gained in the field of network setup and administration, repair and maintenance of personal computers, scanning and printing devices. Skills were acquired in repairing and setting up workstations, laser and inkjet printers, as well as installing servers and preparing workstations for work. Bibliography 1. Mark Minasi “Your PC: design, principle of operation, modernization, maintenance and repair”, St. Petersburg: CORONA print, 2004. 2. PC World magazine 3. www.morePC.ru 4. Lectures “Maintenance of SVT and CS” 5. “Local network hardware.” Encyclopedia. M. Guk - St. Petersburg; publishing house "Peter", 2000. 6. “Computer networks. Principles, technologies, protocols." V.G.Olifer, N.A.Olifer - St. Petersburg; publishing house "Peter", 2000. 7. Regulations Lepse plant. Introduction Introduction Today the whole world communicates using computers. Every family has high-tech machines; no enterprise operates without them. But not everyone knows how to talk to a computer in its language and make it understand human language. Being a computer geek means being one step ahead of the times. After all, nothing in the world develops as quickly as computer technology. It’s not for nothing that they say: “The computer is outdated as soon as it went on sale.” Having learned how computer systems work, you begin to understand the language of numbers, know computer-aided design systems, microprocessor systems and peripheral equipment. In other words, you begin to speak the same language with the computer. He, like a friend, teaches how to solve problems, assess risks and make decisions in non-standard situations, which is highly valued by employers. The range of application of the knowledge of a computer network specialist is wide: from small salons to large enterprises - wherever there are computers, a system administrator is required - a specialist in computer systems and complexes. In order to better prepare specialists in this profession, practical skills are required. This is why educational institutions provide practical classes. Internship in a specialty profile is a form of training in organizations (enterprises) of different forms of ownership and organizational and legal forms. Internship in the specialty profile is carried out with the aim of studying the general principles of functioning of organizations and institutions for labor management and regulation of social and labor relations, employment services; principles of organizing the work of services and departments involved in the selection, placement and accounting of personnel, personnel departments, labor and wages, personnel management departments; as well as analysis of documentation supporting the activities of these services. It allows you to combine theoretical training with practical activities in specific workplaces. The tasks of the practice include:
Chapter 1. Analysis of the organization's structure, description of the organization's hardware and software 1.1. Organization structure Principle Company is one of the largest companies in Smolensk, specializing in the production and sale of computers, solving network integration issues, as well as the supply of office and mobile equipment, components and consumables. The stores offer the widest selection of modern computer equipment: personal and laptop computers, monitors, office equipment from the world's leading manufacturers (Samsung, Acer, Phillips, Toshiba, MSI, Intel, AMD, Asus, Dell, LG, Canon, Epson and many others). Huge selection of consumables (paper, cartridges for inkjet and laser printers, toner, ink, etc.) Today it is a supplier to many large government and commercial organizations in Smolensk and the Smolensk region. It also became the first Smolensk manufacturer of computers certified according to GOST and having an international quality certificate ISO 9001. This allows us to speed up and simplify the process of servicing our clients’ equipment and offer computers highest quality at the best prices. It is the first Smolensk company to be a Gold Certified Partner of Microsoft with the competence “License Management in Organizations” and offers customers software under various licensing programs, which allows them to choose the best option. 1.2. Description of the organization's hardware Nowadays, the overwhelming majority of organizations use modern automated systems And computer equipment, software and storage media. The institution uses 12 computers. Workplace computer hardware includes:
The PC system software for the workplace includes:
Minimum requirements for computer architecture when installing this OS:
The organization has an S5000MB (S5332LNi) server installed as a server computer: Core i5-4590 / 8 GB / 2 x 1 TB SATA RAID. The server computer hardware includes:
The organization uses the following peripheral devices HP LASERJET P2035, HP LASERJET PRO COLOR CP1025, HP LASERJET PRO P1102, HP SCANJET 300, Samsung ML-1210 1.3. Description of software used in the organization Microsoft Windows XP Professional software is used as the operating system. Personal computer software:
Windows XP Professional is an operating system (OS) of the Windows NT family of Microsoft Corporation. It was released on April 25, 2005 as Windows version XP for the personal computer platform. Kaspersky Antivirus (KAV) is antivirus software developed by Kaspersky Lab. Provides the user with protection against viruses, Trojans, spyware, rootkits, adware, as well as unknown threats using proactive protection, including the HIPS component (only for older versions called "Kaspersky Internet Security 2009+, where '+' is the serial number of the previous register, increased annually by one in accordance with the year number , following the year of release of the next version of the antivirus"). Initially, in the early 1990s, it was called -V, then AntiViral Toolkit Pro. 1C: Enterprise is a system of programs for automating various areas of economic activity. A specific software product included in the 1C: Enterprise software system includes those functions and capabilities that meet the purpose of this product. All components of the 1C: Enterprise program system can be divided into Technology Platform and Configurations. The technological platform is a set of various mechanisms used to automate economic activities and do not depend on specific legislation and accounting methodology. Configurations are actually application solutions. Each configuration is focused on automating a certain area of economic activity and, of course, complies with the adopted legislation. “1C: Trade and Warehouse” is designed to record all types of trade transactions. Thanks to its flexibility and customizability, the system is capable of performing all accounting functions - from maintaining directories and entering primary documents to obtaining various statements and analytical reports. “1C: Trade and Warehouse” automates work at all stages of an enterprise’s activities and allows you to:
In “1C: Trade and Warehouse” you can:
“1C: Trade and Warehouse” contains tools to ensure the safety and consistency of information:
Server computer software Windows 2000 Server is a feature-rich operating system that provides the functions of a file and print server, an application server, a Web server, and a communications server. New system Compared to the previous one, it provides greater reliability, speed and ease of control. More importantly, Windows 2000 Server has a large set of distributed services built on top of Active Directory- a multi-purpose, scalable catalogue, created using Internet technologies and fully integrated with the system. Active Directory greatly simplifies system administration and searching for resources on a corporate network. The numerous Web and Internet services included with Windows 2000 Server enable organizations to make extensive use of Internet technologies by creating complex Web applications and streaming services (audio, video, etc.) and using Windows 2000 Server as their platforms for building intranet networks. Windows 2000 Server is a future-proof target and tools platform for Independent Software Vendors (ISVs) and custom business application developers as it supports and enhances the most advanced distributed application services such as DCOM, transaction servers, and message queuing. . Moreover, to increase Windows performance 2000 Server, the base product in the Microsoft server family, supports multi-processor symmetric processing (SMP) on two processors and up to 4 GB of memory. 1.4. Description of the activities of the organization’s information technology department System administrator responsibilities: 1. Installs operating systems and software necessary for operation on servers and workstations. 2. Configures software on servers and workstations. 3. Maintains the software of servers and workstations in working condition. 4. Registers local network users and mail server, assigns IDs and passwords 5. Provides technical and software support to users, advises users on the operation of the local network and programs, draws up instructions for working with the software and brings them to the attention of users. 6. Sets access rights and controls the use of network resources. 7. Ensures timely copying, archiving and backup of data. 8. Takes measures to restore the functionality of the local network in the event of failures or failure of network equipment. 9. Identifies user and software errors and takes action to correct them. 10. Monitors the network, develops proposals for the development of network infrastructure. 11. Provides network security (protection from unauthorized access to information, viewing or changing system files and data), security of internetwork interaction. 12. Provides anti-virus protection of the local computer network, servers and workstations. 13. Prepares proposals for the modernization and acquisition of network equipment. 14. Monitors the installation of local network equipment by specialists from third-party organizations. 15. Informs his immediate supervisor about cases of violation of the rules for using the local computer network and the measures taken. Chapter 2. Ensuring stable operation of computer systems and complexes 2.1. A list of instructions necessary for organizing a workplace for a computer systems engineer or a hardware and software systems engineer. Hardware and software adjuster - a specialist who manages the operation of a computer and configures certain types equipment related to computer equipment and information support. The scope of activity of this profession is the installation, maintenance and modernization of computer equipment, including hardware and software of personal computers, servers, as well as peripheral devices, equipment and computer office equipment. Labor tools (main types of equipment and technologies used) – hardware and software of personal computers and servers; - periphery equipment; – multimedia equipment; – information resources of local and global computer networks. Main types of work (labor activities) – maintenance of hardware of personal computers, servers, peripheral devices and equipment, computer office equipment; – installation and maintenance of software for personal computers, servers, peripheral devices and equipment; – modernization of hardware of personal computers, servers, peripheral devices and equipment; – modernization of software for personal computers, servers, peripheral devices and equipment. Professional competencies – put computer equipment into operation; – diagnose the performance, troubleshoot problems and failures of computer hardware; – replace consumables used in computer and office equipment; – install operating systems on personal computers and servers, as well as configure the user interface; – administer operating systems of personal computers and servers; – install and configure the operation of peripheral devices and equipment; – install and configure application software for personal computers and servers; – diagnose the performance, troubleshoot problems and failures of the operating system and application software; – optimize the configuration of computer equipment depending on the requirements and tasks solved by the user; – remove and add components of personal computers and servers, replace them with compatible ones; – replace, remove and add major components of peripheral devices, equipment and computer office equipment; – update and remove versions of operating systems of personal computers and servers; – update and remove versions of application software of personal computers and servers; – update and remove device drivers for personal computers, servers, peripheral devices and equipment; – update the firmware of computer components, servers, peripheral devices and equipment 2.2. Studying the system of preventive maintenance of computers in an organization Safety requirements before starting work
Safety requirements during operation
Safety requirements in emergency situations
Safety requirements after completion of work
Studying the system of preventive maintenance of computers in an organization Types of SVT maintenance The type of maintenance is determined by the frequency and complex of technological operations to maintain the operational properties of the equipment. GOST 28470-90 “System for maintenance and repair of technical means of computer technology and information science” defines the following types of maintenance
Regulated maintenance must be carried out to the extent and taking into account the operating time provided for in the operational documentation for the SVT, regardless of the technical condition. Periodic maintenance must be performed at intervals and to the extent specified in the operational documentation for the SVT. Maintenance with periodic monitoring must be carried out with the frequency of monitoring the technical condition of the equipment established in the technological documentation and the necessary set of technological operations depending on the technical condition of the equipment. Maintenance with continuous monitoring must be carried out in accordance with the operational documentation for the equipment or technological documentation based on the results of continuous monitoring of the technical condition of the equipment. Monitoring the technical condition of the equipment can be carried out in static or dynamic modes. In the static mode, the control values of voltage and frequency of synchronizing pulses remain constant throughout the entire preventive control cycle, and in the dynamic mode, they are periodically changed. Thus, by creating heavier operating modes of the SVT, it is possible to identify elements that are critical in terms of reliability. Preventive control is carried out in hardware and software. Hardware control is carried out using special equipment, instrumentation and stands, and software and hardware systems. Troubleshooting work during preventive monitoring can be divided into the following stages:
Currently, the following types of maintenance systems (MSS) are most widespread:
Planned preventive maintenance is based on the calendar principle and implements regulated and periodic maintenance. These works are carried out in order to maintain SVT devices in good condition, identify failures in equipment, and prevent failures and failures in the operation of SVT. The frequency of scheduled maintenance depends on the type of equipment and operating conditions (number of shifts and workload). Advantages of the system: ensures the highest availability of SVT. Disadvantages of the system: it requires large material and physical costs. In general, the system includes the following types of maintenance (prevention):
KO, ETO SVT includes inspection of devices, test run quick check readiness (operability of devices), as well as work provided for daily prevention (in accordance with the operating instructions) of all external devices(cleaning, lubrication, adjustment, etc.). During a two-week maintenance, diagnostic tests are run, as well as all types of two-week preventative maintenance provided for external devices. Monthly maintenance provides for a more complete check of the functioning of the SVT using the entire system of tests included in its software. The test is carried out at the nominal values of the power supplies with a preventive voltage change of + 5%. Preventative voltage changes allow you to identify the weakest circuits in the system. Typically, circuits should remain operational when the voltage changes within specified limits. However, aging and other factors cause gradual changes in the performance characteristics of the circuits, which can be detected in prophylactic regimens. Checking the SVT with a preventive change in voltage reveals predictable faults, thereby reducing the number of hard-to-locate faults that lead to failures. During monthly prophylaxis, all necessary work provided in the operating instructions for external devices. During semi-annual (annual) maintenance (STO), the same work is carried out as during monthly maintenance. As well as all types of semi-annual (annual) preventive maintenance: disassembling, cleaning and lubrication of all mechanical components of external devices with their simultaneous adjustment or replacement of parts. In addition, cables and power bars are inspected. A detailed description of preventive maintenance is given in the operating instructions for individual devices supplied to the SVT by the manufacturer. When performing maintenance based on technical condition, maintenance work is unscheduled and is performed as necessary based on the condition of the object (test results), which corresponds to maintenance with continuous monitoring or maintenance with periodic monitoring. Unscheduled preventive maintenance includes extraordinary preventive maintenance, prescribed mainly after the elimination of serious malfunctions of the equipment. The scope of preventive measures is determined by the nature of the malfunction and its possible consequences. SVT can also be placed on unscheduled maintenance when the number of failures occurring over a certain specified period of time exceeds the permissible values. The system requires the availability and correct use of various testing tools (software). The system makes it possible to minimize the cost of operating the SVT, but the readiness of the SVT for use is lower than when using a scheduled preventative service station. With a combined maintenance system, “minor types of maintenance” are carried out as needed, as with condition-based maintenance based on the operating time and operating conditions of a particular type of equipment or the results of its testing. It is planned to carry out “senior types of maintenance” and repairs. The rational organization of the service station should provide for the accumulation of static material based on the results of the operation of the equipment for the purpose of its generalization, analysis and development of recommendations for improving the service structure, increasing the efficiency of use of the equipment, and reducing operating costs. List of necessary material and technical means for organizing and carrying out maintenance work on SVT The quality of operation of the computer depends on the provision of spare parts, various devices, consumables, provision of control and measuring instruments, tools, etc. Of great importance is also the creation of the necessary conditions for the normal functioning of computing facilities (temperature and humidity conditions, power supply conditions, etc.) . etc.) and for operating personnel (climatic conditions, noise level, lighting, etc.). The operation of SVT must be carefully planned. Planning should cover the entire range of issues related to both the preparation of a general program of work for computer equipment, the distribution of computer time, etc., and to the entire work of maintenance personnel. Rational organization of operation should provide for the accumulation of static material based on the results of operation of the equipment for the purpose of its generalization, analysis and development of recommendations for improving the service structure, increasing the efficiency of use of the equipment, and reducing operating costs Diagnostic programs For PCs, there are several types of diagnostic programs (some of them are supplied with the computer) that allow the user to identify the causes of problems that occur in the computer. Diagnostic programs used in PCs can be divided into three levels:
Power On Self Test (POST) POST is a sequence of short routines stored in the ROM BIOS on system board. They are designed to check the main components of the system immediately after it is turned on, which, in fact, is the reason for the delay before loading the operating system. Every time you turn on your computer, the following basic components are automatically checked:
These tests are performed quickly and are not very thorough; if a faulty component is detected, a warning or error (fault) message is issued. Such faults are sometimes called fatal errors. The POST procedure typically provides three ways to indicate a fault:
When the POST procedure detects a malfunction, the computer emits characteristic sound signals, which can be used to identify the faulty element (or group of elements). If the computer is working properly, you will hear one short beep when you turn it on; if a malfunction is detected, a whole series of short or long sound signals, and sometimes a combination of them. The nature of the beep codes depends on the BIOS version and the company that developed it. On most PC-compatible models, the POST procedure displays the progress of testing the computer's RAM on the screen. If a problem is detected during the POST procedure, a corresponding message is displayed, usually in the form of a multi-digit numeric code, for example: 1790- Disk 0 Error. Using the operation and service manual, you can determine which fault corresponds to this code. Error codes issued by the POST procedure to the I/O ports A lesser-known feature of this procedure is that at the beginning of each test, POST issues test codes at the address of a special I/O port that can only be read by a special adapter card installed in the expansion slot. The POST board is installed in the expansion slot. While the POST procedure is running, its built-in indicator will rapidly change to two-digit hexadecimal numbers. If the computer unexpectedly stops testing or freezes, this indicator will display the code of the test that failed during execution. This allows you to significantly narrow down the search for a faulty element. On most computers POST codes to I/O port 80h Operating system diagnostic programs There are several diagnostic programs included in DOS and Windows operating systems. Which ensure testing of SVT components. Modern diagnostic programs have graphical shells and are part of the operating system. Such programs are, for example:
All of the programs listed are available on Windows. Diagnostic programs of equipment manufacturers Equipment manufacturers produce special specialized programs for diagnosing specific equipment, a specific manufacturer. The following groups of programs can be distinguished:
Diagnostic programs for general and special purposes Most test programs can be run in batch mode, allowing you to run a series of tests without operator intervention. You can create an automated diagnostic program that is most effective if you need to identify possible defects or perform the same sequence of tests on several computers. These programs check all types of system memory: main (base), extended (expanded) and additional (extended). The location of the fault can often be determined with precision down to the individual chip or module (SIMM or DIMM) There are a great many such programs. This type of software can be divided into the following categories:
Information programs Used in situations where it is necessary to find out the detailed configuration and maximally test the computer for performance without disassembling system unit or when, at first glance, everything works fine, but the user claims that his computer is constantly buggy and starts every now and then. Or after repairs, for example, replacing electrolytic capacitors with motherboard, you need to conduct a thorough diagnostic to make sure that the computer is working properly. They test a computer or individual components and provide detailed information about its condition, functionality, and possible software and physical problems. Test programs They work on the principle of maximum load with various operations that emulate the user’s work at the computer, and measure the overall performance of the system or the performance of individual components based on comparison with an existing database. Universal programs Programs that combine two categories of programs – informational and test. They allow you not only to test your PC, but also to obtain comprehensive information about its components. There are several completely different versions of the program, but they are all focused exclusively on measuring video system performance. When you start the program, in the main window you will see only the video card model and monitor characteristics. To get more detailed information, click on SystemInfo, there you can find out the processor model, cache size, directX version and other system information. The program allows you to select all or only some tests. Almost all tests are carried out twice, at low and high detail, which gives greater accuracy. After the test, the program displays the result in the form of points that can be compared with another computer. The main thing is that a video system test cannot be done without a critical load on other computer components. And if the computer under test copes with them, then most likely the main components are in order Among service utility packages, without a doubt, the “first among equals” is NortonUtilities, produced by Symantec and has already reached version 2001. The SystemInformation utility included in the package provides conveniently grouped information on all the main components of the computer. It is possible to drill down information into some sections, as well as generate a report. Information about the efficiency and use of the disk is presented quite clearly and colorfully, using pie charts. You can test the processor by clicking the Benchmark button. The program displays a graph of the approximate performance of your system; the unit of measurement is the performance of a PC based on Intel processor 386SX-16MHz. Service equipment To troubleshoot and repair a PC, you need to have special tools that allow you to identify problems and fix them quickly and easily. These include:
Service equipment is a set of devices designed specifically for diagnosing, testing and repairing SVT. Service equipment includes the following elements:
Test instruments and test connectors for testing PC ports The following measuring instruments are used to check and repair PCs:
Test connectors provide software and hardware testing of PC I/O ports (parallel and serial). Computer power supply testing equipment provides testing of PC power supplies and determining their main characteristics. It is a set of equivalent loads, switching elements and measuring instruments. 2.3. Description of monitoring, diagnostics and restoration of computer systems and complexes. Status analysis and troubleshooting "SamsungML-1210" The printer does not pick up paper. The problem is with the pickup roller. Preventative maintenance needs to be done. Technical description "SamsungML-1210" Main characteristics:
Other characteristics:
Eliminating the causes of malfunctions and failures of the SamsungML-1210 The front cover opens, 2 screws are unscrewed. Unscrew the 4 screws at the back. The back wall and top cover are removed, the paper guides are removed and the side walls are removed. Unscrew the 3 screws that hold the laser. 2 connectors located on the sides are disconnected. Wipe the glass with a cotton swab or a clean piece of rag. The pickup roller itself, which is held by 2 self-tapping screws, is unscrewed and cleaned with a special liquid. At the same time, the brake pad is cleaned. It is located in the device under the pickup roller. Then the printer itself is cleaned. This operation can be performed with a vacuum cleaner or compressor. Assembly is carried out in reverse order. 2.4. Identification of deficiencies in the system for ensuring stable operation of computer systems and complexes. Suggestions for improving this system The disadvantage of this organization is the lack of a maintenance schedule for PCs and peripheral equipment. In this regard, this schedule was proposed and developed. Chapter 3. Description of the information system used in the organization 3.1 Domain analysis for an information system Students, organized in groups, study in one of the specialties. Teachers participate in the educational process. The educational process is regulated by the curriculum, indicating the number of hours for each discipline and forms of control (test, exam). The teacher can teach classes in one or more disciplines. 3.2 Analysis/development of information system structure This figure shows structural scheme program execution, which means that information from reference books is taken into the document. A use case diagram (use case diagram) in UML is a diagram that reflects the relationships between actors and use cases and is an integral part of a use case model that allows you to describe a system at a conceptual level. A precedent is a possibility of a modeled system (part of its functionality), thanks to which the user can obtain a specific, measurable and desired result. A use case corresponds to a separate service of the system, defines one of the options for its use and describes a typical way of user interaction with the system. Use cases are typically used to specify external system requirements . 3.3 Description of the database management system/software used for development The 1C: Enterprise 8 software system includes a platform and application solutions developed on its basis for automating the activities of organizations and individuals. The platform itself is not a software product for use by end users, who typically work with one of many application solutions (configurations) developed on the platform. This approach allows you to automate various types of activities using a single technology platform. 3.4. Instructions for users to work with the information system 3.4.1 Purpose of the program The program allows you to:
advantages of the program « automobile enterprise information system":
Functional purpose
Operational purpose The program should be used in enterprises focused on the automotive industry, namely passenger and freight transportation. Users of the program must be employees of the auto industry. Composition of functions The program provides the ability to perform the following functions:
3.4.2 Program execution conditions The climatic operating conditions under which the specified characteristics must be ensured must meet the requirements for technical means in terms of their operating conditions. Minimum composition of technical means The technical means must include an IBM-compatible personal computer (PC), including:
Minimum software components System software used by the program must be a licensed localized version of the operating system. You can use update package 8.3.5.1284. 3.4.3 Program execution Starting the program The program is launched by double-clicking the left mouse button on the “1C: Enterprise 8.3” program shortcut, then you need to select the “WIS Base” configuration and click “Configurator”. The selection window is shown in Figure 1. Figure 1 – Launch information base After launch software module in the “1C: Enterprise 8.3” system, the “1C: Enterprise 8.3 system working window” will appear on the screen, it displays a menu and toolbar in accordance with the user selected, it looks like this: the system working window is shown in Figure 2. Figure 2 – Appearance configuration menu Working with the menu This menu can be divided into:
You can select the basic actions for editing and customizing a document, from creating and saving a new document to setting access rights to the infobase. You can also customize the interface for a specific user and use the help provided by the program to make your work easier. The main menu is the “Configuration” menu, because it creates the structure of the information base. Each configuration object has a unique set of properties. This set is described at the system level and cannot be changed during the task configuration process. The set of properties of a configuration object is determined mainly by its purpose in the 1C: Enterprise system. The main property of any configuration object is the name - the short name of the configuration object. When creating a new configuration object, it is automatically assigned a conditional name consisting of a word determined by the type of object and a number. This name can be changed while editing the properties of the configuration object, while the system monitors the uniqueness of the names. The configuration object name cannot be empty and cannot be longer than 255 characters. Some properties from the entire set of properties inherent in a configuration object are available for editing and can be changed in one way or another during the system configuration process. The nature of changes and their limits are also specified at the system level. A specialist configuring a system can achieve the required behavior of the object during system operation by purposefully changing the properties of a configuration object. 3.4.4 Messages to the operator Since the program is not a console program (with a command line interface), but with a graphical user interface, classic text messages not expected. Error messages appear as windows on the desktop. Shown in Figure 3.
3.5 Description of means and techniques for protecting information when working with the information system 1C: Enterprise supports the ability to upload/download an information base to a file. This mechanism is intended, first of all, to obtain an image of the infobase, regardless of the method of data storage. For example, loading/unloading an infobase into a file can be used to convert the file version to a client-server version. Sometimes this mode is also used to create a backup copy of the information base, however, this option of using it has a number of disadvantages. The main disadvantage of this method of creating a backup is the need to use single-user mode to carry out this operation. With a large volume of information base, the interruption in user work can be quite large, which is not always acceptable. Depending on the operating mode of 1C: Enterprise (file or client-server), we can recommend the following methods for creating a backup copy of the information base: 1) When using the file option 1C: Enterprise 8, you can organize the process of creating a backup copy of the information base by simply copying the 1CV8.1CD file to a separate directory or using software for data backup and recovery. It should be taken into account that to ensure the integrity and consistency of data during the creation of a backup copy, users should be prohibited from working with the infobase, however, the time required to create a backup copy is significantly less than when using uploading the infobase to a file. 2) When using the client-server version of 1C: Enterprise 8, it becomes possible to create a backup copy of the information base using a DBMS. For example, SQL Server allows you to perform backup data while the database is in multi-user mode and available to all users. Using these methods provides the most accurate copy of the infobase state, which cannot always be obtained when using the infobase loading/unloading mode. For example, if there are violations in the database, then during unloading some information may not be unloaded, while during copying all information will be preserved, and after recovery it will be possible to correct the database. The time spent by the information base in single-user mode is also significantly reduced in the case of the file version of 1C: Enterprise 8, and in the case of the client-server version, single-user mode is not used at all. In addition, the positive point is that when using the listed methods, you can use various specialized software tools to create backup copies. Conclusion During the internship in the field of 230000 Informatics and Computer Engineering in specialty 230113 Computer systems and complexes the following tasks were completed: Formation and development of general and professional competencies in the field of the chosen specialty; Acquisition and formation of the necessary skills, abilities and practical experience to solve professional problems in the conditions of a specific enterprise (organization) of the city and region;
As a result of industrial practice, experience was gained in supporting workstations in working order, as well as in analyzing and structuring knowledge about information system branch. List of sources used 1. Baidakov V., Dranishchev V, Krayushkin A, Kuznetsov I, Lavrov M, Monichev A. 1C: Enterprise 8.0 Description of the built-in language. [Text]/ .In 4 volumes. - M.: Firm "1C", 2004. -2575 p. |
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